Scientist believe the protective effect could be linked to anthocyanins, a type of flavonoid that may help open up arteries and counter the build-up of fatty deposits on blood vessel walls.

"We have shown that even at an early age, eating more of these fruits may reduce risk of a heart attack in later life," said nutritionist Dr Aedin Cassidy, from the University of East Anglia, who took part in the research.

The scientists took account of risk factors such as age, high blood pressure, body mass, lack of exercise, smoking, caffeine and alcohol consumption, and family medical history, that could have influenced the results.

Other foods may have similar benefits, say the researchers. Strawberries and blueberries were chosen for the study because they are the most commonly eaten berries in the US.

Victoria Taylor, senior dietitian at the British Heart Foundation, said: "This study found an association between a diet rich in red and purple fruits, such as blueberries, blackberries and strawberries, and a reduction in heart attack risk for young and middle-aged women.

"However, more research is needed to understand why this link between berries and better heart health exists. We would need to know more before we make specific recommendations about individual fruit and vegetables in relation to heart disease.

"But in the meantime, this is yet another good reason to make sure we get our five a day and enjoy the wide variety of fruit and vegetables available to us."

From carrots and kale to grapefruit and clementines, here are more top superfoods for January.

January Superfoods

January Superfoods

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Clementines

Why we love them: Just one of these sweet citrus picks contains 60 percent of your daily recommended intake of vitamin C.
How to enjoy: These perfectly-portable fruits are easy to grab and go. Or try adding a few slices to your next winter salad. When paired with a dash of vitamin C, the iron in leafy greens like kale and spinach becomes easier for the body to absorb.